proc.c

Apache 2.0.63 is the current stable version of the 2.0 series, and is recommended over any previous

        }

        if (attr->cmdtype == APR_PROGRAM ||
            attr->cmdtype == APR_PROGRAM_ENV ||
            *progname == '/') {
            /* for both of these values of cmdtype, caller must pass
             * full path, so it is easy to check;
             * caller can choose to pass full path for other
             * values of cmdtype
             */
            if (access(progname, R_OK|X_OK) == -1) {
                /* exec*() in child wouldn't have worked */
                return errno;
            }
        }
        else {
            /* todo: search PATH for progname then try to access it */
        }
    }

    if ((new->pid = fork()) < 0) {
        return errno;
    }
    else if (new->pid == 0) {
        int status;
        /* child process */

        /*
         * If we do exec cleanup before the dup2() calls to set up pipes
         * on 0-2, we accidentally close the pipes used by programs like
         * mod_cgid.
         *
         * If we do exec cleanup after the dup2() calls, cleanup can accidentally
         * close our pipes which replaced any files which previously had
         * descriptors 0-2.
         *
         * The solution is to kill the cleanup for the pipes, then do
         * exec cleanup, then do the dup2() calls.
         */

        if (attr->child_in) {
            apr_pool_cleanup_kill(apr_file_pool_get(attr->child_in),
                                  attr->child_in, apr_unix_file_cleanup);
        }

        if (attr->child_out) {
            apr_pool_cleanup_kill(apr_file_pool_get(attr->child_out),
                                  attr->child_out, apr_unix_file_cleanup);
        }

        if (attr->child_err) {
            apr_pool_cleanup_kill(apr_file_pool_get(attr->child_err),
                                  attr->child_err, apr_unix_file_cleanup);
        }

        apr_pool_cleanup_for_exec();

        if (attr->child_in) {
            apr_file_close(attr->parent_in);
            dup2(attr->child_in->filedes, STDIN_FILENO);
            apr_file_close(attr->child_in);
        }

        if (attr->child_out) {
            apr_file_close(attr->parent_out);
            dup2(attr->child_out->filedes, STDOUT_FILENO);
            apr_file_close(attr->child_out);
        }

        if (attr->child_err) {
            apr_file_close(attr->parent_err);
            dup2(attr->child_err->filedes, STDERR_FILENO);
            apr_file_close(attr->child_err);
        }

        apr_signal(SIGCHLD, SIG_DFL); /* not sure if this is needed or not */

        if (attr->currdir != NULL) {
            if (chdir(attr->currdir) == -1) {
                if (attr->errfn) {
                    attr->errfn(pool, errno, "change of working directory failed");
                }
                exit(-1);   /* We have big problems, the child should exit. */
            }
        }

        if ((status = limit_proc(attr)) != APR_SUCCESS) {
            if (attr->errfn) {
                attr->errfn(pool, errno, "setting of resource limits failed");
            }
            exit(-1);   /* We have big problems, the child should exit. */
        }

        if (attr->cmdtype == APR_SHELLCMD ||
            attr->cmdtype == APR_SHELLCMD_ENV) {
            int onearg_len = 0;
            const char *newargs[4];

            newargs[0] = SHELL_PATH;
            newargs[1] = "-c";

            i = 0;
            while (args[i]) {
                onearg_len += strlen(args[i]);
                onearg_len++; /* for space delimiter */
                i++;
            }

            switch(i) {
            case 0:
                /* bad parameters; we're doomed */
                break;
            case 1:
                /* no args, or caller already built a single string from
                 * progname and args
                 */
                newargs[2] = args[0];
                break;
            default:
            {
                char *ch, *onearg;
                
                ch = onearg = apr_palloc(pool, onearg_len);
                i = 0;
                while (args[i]) {
                    size_t len = strlen(args[i]);

                    memcpy(ch, args[i], len);
                    ch += len;
                    *ch = ' ';
                    ++ch;
                    ++i;
                }
                --ch; /* back up to trailing blank */
                *ch = '\0';
                newargs[2] = onearg;
            }
            }

            newargs[3] = NULL;

            if (attr->detached) {
                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
            }

            if (attr->cmdtype == APR_SHELLCMD) {
                execve(SHELL_PATH, (char * const *) newargs, (char * const *)env);
            }
            else {
                execv(SHELL_PATH, (char * const *)newargs);
            }
        }
        else if (attr->cmdtype == APR_PROGRAM) {
            if (attr->detached) {
                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
            }

            execve(progname, (char * const *)args, (char * const *)env);
        }
        else if (attr->cmdtype == APR_PROGRAM_ENV) {
            if (attr->detached) {
                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
            }

            execv(progname, (char * const *)args);
        }
        else {
            /* APR_PROGRAM_PATH */
            if (attr->detached) {
                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
            }

            execvp(progname, (char * const *)args);
        }
        if (attr->errfn) {
            char *desc;

            desc = apr_psprintf(pool, "exec of '%s' failed",
                                progname);
            attr->errfn(pool, errno, desc);
        }

        exit(-1);  /* if we get here, there is a problem, so exit with an
                    * error code. */
    }

    /* Parent process */
    if (attr->child_in) {
        apr_file_close(attr->child_in);
    }

    if (attr->child_out) {
        apr_file_close(attr->child_out);
    }

    if (attr->child_err) {
        apr_file_close(attr->child_err);
    }

    return APR_SUCCESS;
}

APR_DECLARE(apr_status_t) apr_proc_wait_all_procs(apr_proc_t *proc,
                                                  int *exitcode,
                                                  apr_exit_why_e *exitwhy,
                                                  apr_wait_how_e waithow,
                                                  apr_pool_t *p)
{
    proc->pid = -1;
    return apr_proc_wait(proc, exitcode, exitwhy, waithow);
}

APR_DECLARE(apr_status_t) apr_proc_wait(apr_proc_t *proc,
                                        int *exitcode, apr_exit_why_e *exitwhy,
                                        apr_wait_how_e waithow)
{
    pid_t pstatus;
    int waitpid_options = WUNTRACED;
    int exit_int;
    int ignore;
    apr_exit_why_e ignorewhy;

    if (exitcode == NULL) {
        exitcode = &ignore;
    }

    if (exitwhy == NULL) {
        exitwhy = &ignorewhy;
    }

    if (waithow != APR_WAIT) {
        waitpid_options |= WNOHANG;
    }

    do {
        pstatus = waitpid(proc->pid, &exit_int, waitpid_options);
    } while (pstatus < 0 && errno == EINTR);

    if (pstatus > 0) {
        proc->pid = pstatus;

        if (WIFEXITED(exit_int)) {
            *exitwhy = APR_PROC_EXIT;
            *exitcode = WEXITSTATUS(exit_int);
        }
        else if (WIFSIGNALED(exit_int)) {
            *exitwhy = APR_PROC_SIGNAL;

#ifdef WCOREDUMP
            if (WCOREDUMP(exit_int)) {
                *exitwhy |= APR_PROC_SIGNAL_CORE;
            }
#endif

            *exitcode = WTERMSIG(exit_int);
        }
        else {
            /* unexpected condition */
            return APR_EGENERAL;
        }

        return APR_CHILD_DONE;
    }
    else if (pstatus == 0) {
        return APR_CHILD_NOTDONE;
    }

    return errno;
}

APR_DECLARE(apr_status_t) apr_procattr_limit_set(apr_procattr_t *attr,
                                                 apr_int32_t what,
                                                 struct rlimit *limit)
{
    switch(what) {
        case APR_LIMIT_CPU:
#ifdef RLIMIT_CPU
            attr->limit_cpu = limit;
            break;
#else
            return APR_ENOTIMPL;
#endif

        case APR_LIMIT_MEM:
#if defined (RLIMIT_DATA) || defined (RLIMIT_VMEM) || defined(RLIMIT_AS)
            attr->limit_mem = limit;
            break;
#else
            return APR_ENOTIMPL;
#endif

        case APR_LIMIT_NPROC:
#ifdef RLIMIT_NPROC
            attr->limit_nproc = limit;
            break;
#else
            return APR_ENOTIMPL;
#endif

        case APR_LIMIT_NOFILE:
#ifdef RLIMIT_NOFILE
            attr->limit_nofile = limit;
            break;
#else
            return APR_ENOTIMPL;
#endif

    }

    return APR_SUCCESS;
}